AGFA d-lab.3 Digital Compact Lab

Scanner
Repair
Prescanner Calibration
Calibration Methods
No. Calibration Remark
1 Finding the zero position Position in which the light sensor responds (Prescanner
moves to the left)
2 Finding the print position Scanner keeps on moving until the density array is
exactly under the right perforation (maximum light)
3 Finding the Scan position Scanner keeps on moving until the density array is
exactly under the left perforation
4 Setting the amplification factors for
the colour arrays for the negative
scan
5 Finding the amplification factors for
the colour arrays to define the lamp
brightness
6 Setting the amplification factors for
density, DX, Perfo
7 Measuring the light without a film
(bright alignment)
The amplification factors are adjusted until no photodiode
is overdriving. The mask factor is switched off
(on 1). Illumination with white light (no IR).
The amplification setting is calculated on the basis of
the setting of the amplification factors for the colour
arrays for the negative scan in such a way that the
photodiodes are driven to half output. This amplification
setting is kept up to the next white balance of the
Main Scanner. The measurement of the lamp brightness
serves to trigger a white balance of the Main
Scanner.
The amplification factors are adjusted until no photodiode
is overdriving. In contrast to the colour arrays,
the mask factor is adjusted as well. Light adjustment
as above.
The resulting values for all photodiodes are used as
reference for the Scan.
8 Measuring the lamp brightness No actual calibration of the Prescanner, but described
here as it is necessary as Trigger for the white balance
of the Main Scanner.
Along with the amplification factors defined before
(half full-scale deflection) the Prescanner moves in
scanning position without a film with white light (no
IR). While it is moving, the measuring values are integrated
for each colour over a fixed path.
If the deviation from the last measuring value is too
important (spectral or in terms of brightness), a new
white balance of the Main Scanner is performed.
If the deviation is small, the measuring values are
used for the correction of the integration times.
Not calibrated
Mask factor (component tolerance, depending on the
selected amplification) and dark Offset
4.4.30 2001-01-02 /PN 9009 AGFA d-lab.3